1. Field of the Invention
The invention relates to an inductive power coupling device for coupling electrical power between two units being rotatable against each other, specifically for power couplers used in computer tomography scanners. Such power couplers are also known as rotary joints.
2. Description of Relevant Art
In computer tomography scanners and other related machines high-power in the range of 10 kW up to more than 100 kW is transferred from the stationary the rotating side. There a high voltage in the range of above hundred kilovolts is generated to produce x-ray radiation. The high voltage and the x-ray radiation may cause physical damage to operating personal under specific conditions like during service when protective covers are open. Furthermore unwanted exposure to x-ray radiation may occur in the case of fault of components responsible for control of the x-ray tube.
In the U.S. Pat. No. 7,054,411 a multiple channel inductive rotary joint is disclosed. It has a first inductive channel for transferring auxiliary power from the stationary to the rotating side. This auxiliary power is required by the control circuits on the rotating side to operate correctly. There is a separated high power inductive channel for transferring x-ray power from primary to secondary side. Furthermore a capacitive feedback link for power control is provided. The disadvantage of this system is the very high complexity, high costs for multiple channels and the high rotating mass due to two inductive rotary joints requiring heavy ferrite cores.